Concrete slab key-joint forming member



April 1969 J. A. JACKSON CONCRETE SLAB KEY'JOINT FORMING MEMBER Filed Jan, 8 1968 )United States Patent 3,437,018 CONCRETE SLAB KEY-JOINT FORMING MEMBER James A. Jackson, Shawnee Mission, Kans., assignor to Meadow Steel Products, Inc., a corporation of Alabama Filed Jan. 8, 1968, Ser. No. 696,322 Int. Cl. EOlc 11/02, 23/02 US. CI. 94-17 4 Claims ABSTRACT 0F THE DISCLOSURE This invention relates to concrete slab key-joint forming members for use in the construction of concrete slabs for roadways, building floors, airfield runways and the like.

An object of my invention is to provide a key-joint forming member for use between adjacent sections of poured concrete which is constructed and arranged to form an interlocking tongue and groove joint between the sections whereby the sections are adapted to expand and contract in a horizontal plane.

A further object of my invention is to provide a keyjoint forming member which is positively secured to the supporting stakes without the necessity of providing additional attaching means therefor, thus greatly facilitating installation of the forming member.

A further object of my invention is to provide a keyjoint forming member of the character designated in which the member is supported on the stakes with vertically extending portions of the member extending along opposite sides of the stake and in vertically spaced relation to each other with the upper end of the member being in vertical alignment with the center of the stakes.

A still further object of my invention is to provide a key-joint forming member of the character designated which shall be simple of construction, economical of manufacture and one which is anchored to the stakes in a minimum of time.

Apparatus embodying features of my invention is illustrated in the accompanying drawing, forming a part of this application, in which:

FIG. 1 is a perspective view, partly broken away and in section, showing the key-joint forming member employed between slabs of poured concrete to form a tongue and groove interlocking joint between adjacent slabs with one slab of concrete being omitted, for the sake of clarity; and,

FIG. 2 is an enlarged, fragmental sectional view showing more clearly the tongue and groove interlocking joint.

Referring now to the drawing for a better understanding of my invention, I show a key-joint forming member which is preferably formed from sheet metal, such as steel, aluminum and the like. The forming member 10 comprises upper and lower vertically extending portions 11 and 12, respectively, which are connected to each other by an intermediate, laterally disposed key deformation portion 13. As shown in FIG. 2, the key deformation portion 13 comprises laterally extending members 14 which preferably extend inwardly toward each other, as shown, and are formed integrally with a vertically extend- 3,437,013 Patented Apr. 8, 1969 ing intermediate member 16 which connects the members 14 to each other.

The upper vertically extending portion 11 extends laterally as at 17 intermediate its upper and lower edges in a direction opposite the direction of the key deformation portion 13 and then extends vertically, as at 18. The upper edge of the upper vertically extending portion 11 is folded over as at 19 in a direction opposite the direction of the key deformation portion 13 to define a depending vertical member 21 which is bent laterally as at 22 directly opposite and away from the lateral bend 17 and then extends downwardly as at 23 to define a downwardly opening recess 24 for receiving the upper ends of stakes 26-. As shown in FIG. 2, the laterally extending portions 17 and 22 abut each other at a point which is in vertical alignment with the upper edge of the elongated sheet member 10. Also, the laterally extending portions 17 and 22 are equal in length to position the stakes in vertical alignment with the upper edge of the elongated forming member 10.

The lower portion 12 of the forming member 10 extends downwardly generally parallel to the upper vertical portion 11 and is spaced laterally from the upper portion 11 in a direction opposite the direction of the key deformation portion 13 a distance equal substantially the thickness of the stakes 26- whereby the lower vertical portion 12 engages the opposite side of the stakes 26 from the side thereof engaged by the vertical portion 11, as shown in FIG. 2. Longitudinally spaced openings 27 are provided in the elongated sheet member 10 adjacent the juncture of the lower vertical portion 12 and the key deformation portion 13 for receiving the stakes 26 whereby the stakes are positively held in place. That is, with the stakes 26 extending through the openings 27 and the upper ends of the stakes 26 being within the downwardly opening recess 24, the stakes are secured to the elongated forming member 10 without the necessity of providing additional securing means. Preferably, the openings 27 are provided by punching out a portion of the metal forming the sheet member 12 whereby the punched-out portion of the metal, indicated at 28, extends upwardly within the key deformation portion 13, as shown.

The lower vertically extending portion 12 is provided with longitudinally extending recesses 29 therein which define longitudinally extending projections 31 which project outwardly opposite the direction of the key deformation portion 13, as shown in FIG. 2. The longitudinally extending projections 31 add strength to the key forming member 10 and at the same time a firm contact is provided between the remaining portion of the lower vertically extending portion 12 and the stake 26 adjacent thereto.

The vertical member 16 of the key deformation portion 13 is provided with longitudinally spaced openings 32 which are adapted to receive metal dowels or rods 33 in a manner well understood in the art.

From the foregoing description, the installation of my improved form for forming a key contraction joint between adjacent concrete slabs will be readily understood. The stakes 26 are driven into the prepared sub-grade, indicated at 34, with the upper ends of the stakes spaced uniformly below grade level, indicated at 36. The stakes 26 are spaced longitudinally from each other whereby they are in alignment with the openings 27 provided in the members 10. The sheet member 10 is positioned on the stakes 26 whereby the upper ends of the stakes pass through the openings 27 and then move upwardly into firm engagement with the laterally extending portions 17 and 22 to thus position the sheet member 10 accurately on the stakes 26 whereby the upper edge 19- of the forming member is flush with the grade level 36, as shown. With the elongated sheet member 10 thus positioned on the stakes 26, the upper vertical portion 11 and the lower vertical portion 12 engage opposite sides of the stake and at the same time the depending portion 23 of the folded over portion of the sheet member 10 engages the upper end of the stake 26 at the side thereof opposite the side engaged by the vertically extended portion 11, as shown in FIG. 2. Also, the Stakes 26 engage the sides of the opening 27 whereby all of these contact points between the elongated sheet member 10 and the stakes 26 positively holds the stake accurately in position.

From the foregoing, it will be seen that I have devised an improved form for forming a key contraction joint between adjacent concrete slabs. By firmly anchoring the elongated sheet member to the longitudinally space stakes, the elongated sheet member is accurately positioned on the stakes and secured thereto without the necessity of additional securing means. Also, by providing firm contact between the supporting stakes and the elongated sheet forming member at a plurality of points, the overall structure is sturdy and positions the stakes accurately in vertical alignment with the upper edge of the elongated sheet member. Furthermore, by providing a self-contained unit which requires no additional securing or anchoring means between the stakes and the elongated forming member, the forming members may be erected in a minimum of time by unskilled labor after the stakes have been driven the proper distance in the sub-grade.

While I have shown my invention in but one form, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various other changes and modifications without departing from the spirit thereof, and I desire, therefore, that only such limitations shall be placed thereupon as are specifically set forth in the appended claims.

What I claim is:

1. In a concrete form for forming a key contraction joint between adjacent concrete slabs wherein a plurality of stakes are set with their upper ends space uniformly below grade level at spaced apart intervals;

(a) an elongated sheet member having spaced apart upper and lower vertically extending portions connected to each other by an intermediate, laterally disposed key deformation portion,

(b) said upper portion having a folded-over portion at the upper edge thereof extending in a direction opposite thev direction of said key deformation portion,

(c) said folded-over portion extending downwardly and defining with said upper vertical portion ad- 4 jacent thereto a downwardly opening recess for receiving and engaging the upper ends of the stakes so that said sheet member is supported on the upper ends of the stakes,

((1) said lower portion extending downwardly generally parallel to said upper portion and being spaced laterally therefrom in a direction opposite the direction of said key deformation portion a distance equal substantially the thickness of the stakes, and

(e) there being longitudinally spaced openings through said sheet member adjacent the juncture of said lower portion and said key deformation portion for receiving the stakes.

2. In a concrete form for forming a key contraction joint between adjacent concrete slabs as defined in claim 1 in which said lower portion is provided with longitudinally extending recesses therein which project outwardly opposite the direction of said key deformation portion.

3. In a concrete form for forming a key contraction joint between adjacent concrete slabs as defined in claim 1 in which said upper portion extends laterally intermediate its upper and lower edges in a direction opposite the direction of said key deformation portion and said folded-over portion extends laterally away from said lateral bend in said upper portion and then downwardly to define a downwardly opening recess for receiving the upper ends of the stakes.

4. In a concrete form for forming a key contraction joint between adjacent concrete slabs as defined in claim 3 in which said upper portion and said folded-over portion extend adjacent and parallel to each other from the upper edges thereof to the point that they extend laterally so that the laterally extending portions abut each other at a point which is in vertical alignment with the upper edge of said elongated sheet and the laterally extending portions are substantially equal in length to position the stakes in vertical alignment with the upper edges of said elongated sheet.

References Cited UNITED STATES PATENTS 2,535,135 12/1950 Jacobson 9417 3,288,042 11/1966 Gaetke 94-51 3,357,324- 12/196'7 Tone et a1 9451 JACOB L. NACKENOFF, Primary Examiner.

U.S. Cl. X.R. 

